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Modeling Line Drop Compensation, Reactive Current Compensation, Cross-Current Compensation. Dmitry Kosterev BPA November 2013. Basics. XT = 12 to 20%. Line Drop Compensation. Generator Terminal Voltage. 01. Reactive Current Compensation.
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ModelingLine Drop Compensation, Reactive Current Compensation, Cross-Current Compensation Dmitry Kosterev BPA November 2013
Basics XT = 12 to 20% Line Drop Compensation Generator Terminal Voltage 01 Reactive Current Compensation gentpj 1 “UNIT1” 13.8 “01”: … “xcomp” 0.05 gentpj 2 “UNIT2” 13.8 “01”: … “xcomp” 0.00 gentpj 3 “UNIT3” 13.8 “01”: … “xcomp” – 0.05
Basics POI Voltage Line Drop Compensation Generator Terminal Voltage Reactive Current Compensation Generator Reactive Power
General Rule 01 02 RCC = – 5% Model: gentpj 1 “UNIT1” 13.8 “01”: … “xcomp” – 0.05 gentpj 1 “UNIT1” 13.8 “02”: … “xcomp” – 0.05
Modeling In General Electric PSLF: “xcomp” is negative for Reactive Current Compensation In Siemens PTI PSS®E: “xcomp” is positive for Reactive Current Compensation Many cases when the data is converted incorrectly between the programs: E.g.Rock Island,Ryan,Magcorp
General Rule Positive “xcomp” will result in sister units becoming unstable (one goes full boost, one goes full buck) if they have different parameters or initial unit loading Voltage Field Voltage Unit 1, Field Voltage Unit 2 Reactive Power Unit 1, Reactive Power Unit 2
Rule Breakers – US ACE and BPA LDC = + 5% 01 02 Cross-Current Compensation
Modeling • Present practice is to use the positive “xcomp” to represent Line Drop Compensation • Cross-compensation is not modeled • John Day, The Dalles and Willamette Valley plants • Models can have “xcomp” positive as long as two sister units have identical models and data, and have the same MW and MVAR output • State estimator models have units dispatched at different MW levels • Need to make sure models are stable
Modeling XCOMP (Existing practice): gentpj 1 “UNIT1” 13.8 “01”: … “xcomp” +0.045 gentpj 1 “UNIT1” 13.8 “02”: … “xcomp” +0.045 CCOMP: gentpj 1 “UNIT1” 13.8 “01”: … “xcomp” 0.0 gentpj 1 “UNIT1” 13.8 “02”: … “xcomp” 0.0 ccomp 1 “UNIT1” 13.8 “01”: “rc” 0.0 “xc” –0.05 “rt” 0.0 “xt” 0.045 XCOMP_CCOMP: gentpj 1 “UNIT1” 13.8 “01”: … “xcomp” 0.045 gentpj 1 “UNIT1” 13.8 “02”: … “xcomp” 0.045 ccomp 1 “UNIT1” 13.8 “01”: “rc” 0.0 “xc” –0.05 “rt” 0.0 “xt” 0.0
Model Testing 01_02 _02 01_ 01 01 01 02 02 02
Model Testing LDC Setting is 4.5% Voltage dip is simulated, effective LDC is measured
Recommendations • Use CCOMP model to represent cross-current compensation when used • Make changes to CCOMP and XCOMP models to work together • If “xt” in “ccomp” is zero, continue using “xcomp” parameter from “gentpj” model • If “xt” in “ccomp” is non-zero, set “xcomp” parameter to zero in “gentpj” model • John Day has +0.045 LDC and cross-current compensatio • Make sure that the following works • Set “xc” to –0.05 and “xt” to 0.0 in “ccomp” model • Set “xcomp” to 0.045 in “gentpj” model